John Fedup
The Bunker Group
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- #61
I would think 4 smaller turbofans might be better than 2 large ones which I would think would be more vulnerable to FOD.
A400m
- Thread starter John Fedup
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Ananda
The Bunker Group
Yes, changing Turboprop to turbofan also the move that Antonov used to rejuvenate AN-70 fortune.
I believe Antonov and Turkey are in talk on AN-188, which basically AN-70 with their 4 Turboprop replace by 4 Turbofans.
Antonov An-188 Military Transport Aircraft - Airforce Technology
So, technically it should not be too difficult for Airbus to make version A-400M with Turbofans (perhaps call it A-410M).
Still isn't part of the Euro deal when making A-400M is the development of the engine it self which being seen as to maintain Euro Engine producers edge ?
I believe Antonov and Turkey are in talk on AN-188, which basically AN-70 with their 4 Turboprop replace by 4 Turbofans.
Antonov An-188 Military Transport Aircraft - Airforce Technology
So, technically it should not be too difficult for Airbus to make version A-400M with Turbofans (perhaps call it A-410M).
Still isn't part of the Euro deal when making A-400M is the development of the engine it self which being seen as to maintain Euro Engine producers edge ?
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I did read a USAF article some time ago that was written after dirt runway trials with the C 17 in which the conclusion was that there was no greater danger of F.O.D. ingestion than a C130 as long as the reversers where turned off below 30 knt.s We must keep in mind that propellers also stir up a lot of debris. Sorry I cannot provide a link as it was just some casual reading I was doing.
Why? Embraer, KHI, and Antonov, don't think so, plus you can also have FOD damage with turboprops where the prop blades are hit and damaged. A damaged prop blade creates all sorts of problems.
Todjaeger
Potstirrer
You might want to check a few things first. Boeing gave customers the option of selecting either GE, P&W, or Rolls-Royce engines when the B777-200 was launched. Also, the B787 is configured so that the aircraft can be fitted with either GE or Rolls-Royce engines, and that a B787 can be re-engined (within 24 hrs per Boeing) with either GE or Rolls-Royce engines so that a GE-powered B787 could be switched and become a Rolls-Royce powered B787.
That sort of flexibility is not quite I would consider 'protectionism' and frankly, with the aeroplane manufacturer not actively involved in the design and production of the engines, they are less apt to care who manufactures the engine, as long as the engine(s) perform to the required specifications and meet the required levels of availability.
EDIT: Additional comment
The USN T-45 Goshawk jet trainer which was manufactured by McD-D and then Boeing following development from the BAE Hawk, uses a RR-Turbomecca turbofan which does indeed suggest that even military aircraft, built in the US and for use by US forces, can include Euro engines...
Not an aerospace engineer, but I do believe that switching an aircraft design from props to fans would trigger a major design and re-certification effort. A change in engines generally could change the weight and trim of an aircraft, as well as the amount of power or thrust available in flight and fuel consumption. A change in engine type could also change the amount of drag an aircraft experiences. Just consider all the potential issues that one would encounter re-engining an automobile with a petrol/gasoline engine with a diesel engine with the same amount of power...
As for the loss of rough strip capability... I would automatically assume a change to turbofans would see a loss of rough strip capability, unless the aircraft & engine was designed to continue to provide a turbofan-powered rough strip capability. IIRC some civilian airliners that operated in some of the more remote areas of some places in South America had their engines fitted with kit to divert some of the potential FOD. Again, that and other options/methods could be utilized, but again these would require some redesign work. Nothing that could not be done or overcome, but it would require more time and resources.
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Vulcan
Member
Have the C-2 and KC-390 demonstrated that capability yet? Any aircraft can claim to have a generic 'rough strip' capability, the devil lies in what grade of FOD causes an actual risk to the aircraft. C-17 taking off from a dirt airstrip doesn't instantly make it not susceptible to FOD in other instances, from memory that testing was done on a dirt runway which had been wetted to represent rainfall.
I also vaguely remember reading way back when during original 1 C-17 testing, they had to cancel testing from semi-prepared strips twice because of FOD damage to the engines and needing extensive repairs.
A turbofan can be viable, but viable doesn't mean efficient nor does it mean equivalent. Put an A400M and a turbofan A400M side by side, one will be more flexible as to which airfields it can fly into at the drop of a hat than the other.
As far as I understand the KC-390 has as part of it's certification and I think the C-2 has. @MrConservative maybe able to clarify that point.
Vulcan
Member
Cool, must've missed it! Caught the C-2 at RIAT last year and that it was a beautiful looking bird. Shame about the sky on departure day!
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Oh yes it is a beautiful bird. Saw it when it was here and a cloudy day makes for good photography so I was told by a photographer. Same aircraft too.
John Fedup
The Bunker Group
- Thread Starter Thread Starter
- #70
It would really depend on the diameter of the turbofans for a twin configuration. As 4 prop jobs are being replaced by 2 turbofans the diameter is likely going to result in a much shorter ground clearance hence a greater threat of FOD. In any event, if the prop engines aren’t sorted within the next year, are operators going to walk away or demand turbofans? Let’s face it, the vendor has had years to address this problem and the only result seems to be “we have a solution and it will fitted soon”. Operators are understandably not impressed.
The KC-390 has had a testing programme on unprepared field capability and the C-2 has had a testing programme on ice surface capability.
The thing about the C-2 was that there are questions relating to the undercarriage setup with respect to rough field because when the project was conceived 20 years ago it was to meet Japanese requirements at the time, which were based around the nations pure self defence posture. The notion of having an expeditionary air mobility capability that would fly to unprepared airstrips in the south pacific was well off the radar. Thus the C-2's under-carriage set up was design to meet the need of Japanese engineered permanent runways.
All offshore Japanese islands both large and small dotted around the archipelago had prepared permanent runways, the shortest was 900m so STOL was a requirement and Hokkaido through the winter frequently has iced runway conditions, thus the ice requirement.
However right throughout the nation there are very few unprepared airstrips like grass, dirt, packed coral or cinder rough runways. Frankly such things are not very Japanese. The very few grass runways that exist are for private light general aviation. This is a land with a love of concrete (Concrete production in Japan totalled 91 million tons in 1994 compared with 78 million tons in the United States) and if there is a need for a runway somewhere they do it properly, with mega tonnes of the hard grey stuff, not some half-arsed 3rd world strip of gravel.
Just for the "dirt strip" certification they'd need a minimum of 2-3 years - that's how long it took the first time, with Airbus renting civilian airfields of various kinds for it between 2013 and 2016 (at least: gras, sand, earth and gravel).
A bigger problem with changing from props to turbo fans is the change of airflow characteristics over the wing which can completely change the stall characteristics of the aircraft. Even small changes can have a dramatic effect in this regard. Just look at the problems Lockheed had with the C130J early in the test program due to the change in the propeller design and the change this made to the airflow over the wing. There was a significant problems with the stall that had to be resolved. There is also a reduction of lift to consider as the higher speed prop wash provides more lift behind the propellers. You would need a completely new wing design if the engine type was changed for both aerodynamic and structural reasons.
John Fedup
The Bunker Group
- Thread Starter Thread Starter
- #74
Redesign of the wing and recertifications would be significant so which is easier, that together with turbofans or a total redesign of the current turboprop system? Lots of wing and turbofan expertise in Europe but turboprop, not so much it seems.
That was the plan but a Rolls engined 787 cannot be repowered with GE engines, the intention was to use a common mounting it this didn’t happen, otherwise all those RR engined 787 parked up would have GE engines now.
And who had an turboprop engine big enough for the job, Pratt didn’t if that who you are thinking of.
John Fedup
The Bunker Group
- Thread Starter Thread Starter
- #77
That’s my point, not much expertise in designing big turboprop engines but there are lots of turbofan options and Airbus has people who can redesign the wing.
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John Fedup
The Bunker Group
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- #79
Germany has refused delivery on two A400Ms. Whether rejection is right or wrong, it must give the French pause wrt German participation in the FCAS program. German export restrictions are problematic as well.
Germany refuses delivery of two A400M transport aircraft
Germany refuses delivery of two A400M transport aircraft
I am still a big fan of the A400m due to its unique features. But I note that the A400M is being produced at the reduced rate of eight per annum (down from a high of 19 achieved in 2017), it should take a further 12 years for it to complete the remaining aircraft, extending work into the early 2030s.
This hurts the export potential for the A400M in the early 2020s. If the engine and propeller gearbox problems continue, Airbus will not get new A400M users like the Koreans. Korean acceptance of the proposed Spain deal with breathe life for its export.
Thanks for the A400M update. Not sure if this is related to the European Aviation Safety Agency certification for a "Pack 2" series of modifications to the TP400-D6 engine's Avio Aero-supplied permanent propeller gearbox.
I continue to scratch my head over the inability of Europrop International GmbH (a JV of four main European aircraft engine manufacturers), to get its act together. In UK Parliament in July, Mark Francois, a former Defence Minister, said: “We have paid £2.6 billion for an aircraft with appalling reliability, bad engines, a virtually broken gearbox, problem propellers, massive vibration problems...”
This hurts the export potential for the A400M in the early 2020s. If the engine and propeller gearbox problems continue, Airbus will not get new A400M users like the Koreans. Korean acceptance of the proposed Spain deal with breathe life for its export.
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